Preliminary Studys On Carotid Artery Parameters Detected By Intracavitary Convex Array Probe

1.Preliminary studys on the carotid artery parameters Detected by Intracavitary Convex Array ProbePurpose and SignificanceFinal results of The North American Symptomatic Carotid Endarterectomy Trial (NASCET) and the MRC European Carotid Surgery Trial(ECST) displayed that carotid artery(CA) must be observed intimately when stegnosis degree is higher than 50%and it must have an operation or interventional therapy in time when stegnosis degree is higher than 70%.Incidence of cerebral infarction can be decreased greatly by therapy.This results in more research about carotid artery made by scholars at home and abroad.Digital subtraction angiography(DSA) has been considered as a gold standard of CA diagnosis.However,It is not received widely for DSA because of its invasion and expensive price.High-frequency ultrasound is considerd as substitute check preferentially Because of its reproducibility,portability and accuracy.However, high-frequency ultrasound has some limitation because of its effect on acoustic wave' penetrating power and inferior maxilla.Especially,internal carotid artery(ICA) cann't be displayed clearly by high-frequency linear array probe when it is used to this patients with obesity,cervical part short and carotid furcation position is higher.These patients is considerable.Thus,some scholars suggested that abdomen low frequency convex array probe should be used to detect ICA.We observed that it can scale-up display length of ICA,obtained fine color flow image and frequency spectrogram, but its 2-D image resolution ratio is lower and its color flow signal is color-spillover. When ICA blood flow is small and its velocity is slow,ICA blood flow signal is not displayed by abdomen low frequency convex array probe because of masking of internal jugular vein.Some scholars reported that transoral intracavitary convex array probe can obtain excellent 2D image and color blood flow image of middle- distal segment ICA.This phenomenon is related possibly to high frequency and resolution of this probe.This method also has powerfully stimulative to throat and degermation difficultly of probe.Illuminated by this study,we detected CCA and ICA by putting this probe on cervical part in our study.Characteristic of this method is that it can get out of disadvantage of abdomen low frequency convex array probe in image resolution and high-frequency linear array probe in penetrating power and transoral intracavitary convex array probe in throat stimulation.Our purpose is approach feasibility of this method.Recently,reports about this aspect isn't read.Materials and Methods1)Study objects:A trial was conducted in the department of ultrasound of Southern Hospital,Southern Medical University,from January 2007 to February 2009.We choosed 86 carotid arteries of 43 patients.We excluded patients who had any follow conditions:(1) cerebral infarction,(2) aortosclerosis,(3) coronary heart disease,(4) doubtful transient ischemic attacks or carotid artery pathological changes.We included(recruited) healthy subjects.All subjects were examined by three different frequency ultrasound probe.Each Carotid Artery is considered as a study objects.2)Equipment:The equipment used was PhilipsIU22 color Doppler ultrasound withL12—5(frequency5～12MHz),C5—2(frequency 2～5MHz) and L9—3 (frequency 3～gMHz) probe.3)Detection method:All subjects were asked to be supine position,pad thin pillow,make head hypsokinesis,sufficiently expose cervical part.They were examined with intracavitary convex array probe,low frequency convex array probe and high-frequency linear probe respectively to collect following data of CCA(common carotid artery) and ICA:ICA visible length,CCA intimae-medial thickness(IMT);CCA and ICA end-diastolic velocity(EDV),peak systolic velocity(PSV),internal diameter,resistent index(RI) color Doppler appearance et al.All operation were finished by same expert ultrasound doctor.4)Statistical analysis:Data were expressed as mean±standard deviation.SPSS 13.0 software was used to analyze the data.The means comparison of IMT and ICAvisible length parameters above measureed by three different frequency ultrasound probe were evaluated statistically by One-Way ANOVA.Others were evaluated statistically by repeated measurement ANOVA and Multiple comparison between means(LSD).The P value below 0.05 was considered statistically significant.Result1) peak systolic velocity(PSV) of ICA and CCA:PSV was recorded with High-frequency linear array probe,low-frequency convex array probe and intracavitary convex array probe,which were put on ICA and CCA.There was significant different on the peak velocity artery during systolic among three groups(P＜0.001),and the rate of blood flow in CCA was faster than that in ICA.From Inter-group comparison,there was significant difference between High-frequency linear array probe and low-frequency convex array probe(P＜0.05, P=0.037),but there was no significant difference between high-frequency linear array probe and cavity convex array probe(P＞0.05,P = 0.074).2)EDV and RI of ICA:EDV of ICA detected with High-frequency linear array probe and low-frequency convex array probe has significant difference(P=0.010),there was significant difference between low-frequency convex array probe and intracavitary convex array probe(P＜0.000),but there was no significant difference between high-frequency linear array probe and intracavitary convex array probe(P＞0.05,P = 0.759).There was significant difference between low-frequency convex array probe and intracavitary convex array probe,between high-frequency linear array probe and cavity convex array probe(P＜0.001) in RI of ICA,but there was no significant difference between low-frequency convex array probe and intracavitary convex array probe(P＞0.05,P = 0.221);3)Visible length of ICA:Observating the length of 86 ICA in 43 patients by three different frequency probes through the 2-D image and color Doppler,there was significant difference among three groups(P＜0.001),which showed that the low-frequency convex array probe was superior to the high-frequency linear array probe and intracavitary convex array probe,and intracavitary convex array probe was superior to high-frequency linear array probe.4) intimae-medial thickness(IMT) and internal diameter of CCA:Measuring the IMT of 86 CCA in 43 cases by three different frequency probes, there were no significant difference among three groups(P＞0.05,between low-frequency convex array probe and intracavitary convex array probe P=0.671; high-frequency linear array probe and intracavitary convex array probe P= 0.722;High-frequency linear array probe and low-frequency convex array probe P=0.945).Comparison to internal diameter of CCA measured by above-mentioned three modes,there was significant difference between high-frequency linear array probe and low-frequency convex array probe(P＜0.001),while there was no significant difference between low-frequency convex array probe and intracavitary convex array probe(P＞0.05,P=0.163).5)2-D image and color-doppler flow signal:On both 2-D image resolution and color flow signal,high-frequency linear array probe was superior to low-frequency convex array probe and intracavitary convex array probe in CCA,but in ICA, low-frequency probe was broader than the other two probe,because of low-frequency and low-resolution,two-dimensional image of low-frequency convex array probe was inferior to the other two probe.Meanwhile,low-frequency convex array probe showed color-spillover phenomenon,while there were better color blood-flow signal in the other two probes.ConclusionVisible length of ICA was lengthened and accurace of ICA flow parameters was elevated which detected by intracavitary convex array probe.As a important image examination tool,intracavitary convex array probe has significant value for detection of middle- distal segment of ICA.2.Value of intracavitary convex array probe in detecting internal carotid arterial diseasePurpose and SignificanceCarotid artery disease is related intimately to brain tissue' blood supply.There are reference value importantly to treatment plan by exactly assessing carotid artery disease.Cerebral vessels incident can be decreased and prevented.High-frequency ultrasound is considered as a detection method used frequently.Treaty methods can be choosed only by sonography outcomes.However,high-frequency ultrasound has some limitation about detection of middle-distal segment ICA.Especially,internal carotid artery(ICA) cann't be displayed clearly by high-frequency linear array probe when it used to this patients with obesity,cervical part short and carotid furcation position is higher.To solve this question,this study will approach value of intracavitary convex array probe in detecting internal carotid arterial disease.Materials and Methods1)Study subjects:A trial was conducted in the department of ultrasound of Southern Hospital,Southern Medical University,from January 2007 to February 2009.We choosed 70 carotid arteries of 35 hospitalized patients,,16men and 19women,all aged from 32 to 80.The mean age of the study population was 60.2±12.1 years old.14 subjects proved by DSA is carotid artery stenosis＞70%.Others is not obviously stenosis.All subjects were examined by three different frequency ultrasound probe.Each Carotid Artery is considered as a study objects.2)Methods:70 internal carotid arteries(ICA) of 35 cases were examined with intracavitary convex array probe and high-frequency linear probe respectively to collect following data:visible length,color Doppler appearance and peak systolic velocity(PSV).PSVICA/PSVCCA ratio was measured in 14 cases of unilateral ICA stenosis diagnosed with DSA to compare the accuracy of evaluating stenosis with two different probes.3) Statistical analysis:All measurement data were expressed as means±SD. Paired t test was used for comparison of paired measurement data among groups,x~2 test was used for comparison of enumeration data between 2 groups.All calculations were made with SPSS 13.0 for Windows.Statistical significance was defined as a value of p＜0.05.ResultVisible length and PSV from high-frequency linear probe and those from intracavitary convex array probe,the difference between them is significant(p＜0.05). Satisfied grey and color Doppler images can be obtained with intracavitary convex array probe in 20 ICA which were difficult to be examined with high-frequency linear probe.15 ICA were detected twisting in "V" or "S" appearance with intracavitary convex array probe,while only 9 ICA were detected in abnormal appearance with high-frequency linear probe.For 14 ICA with 70-99%stenosis diagnosed by DSA, the accuracy of diagnosis is(account for) 78.5%with high-frequency linear probe is, but 92.8%with intracavitary convex array probe.ConclusionIntracavitary convex array probe is an effective complement for ICA inspection with high-frequency linear probe because visible length of ICA could be significantly increased with intracavitary convex array probe which is valuable for detecting pathologic changes in middle or distal parts of ICA.